The DuoTone tool tints shadows and highlights with user-specified colors.

Highlight Color: The Highlight Color wheel allows you to select the color that will tint the highlights in your image.

Tint Highlights: Controls the strength of the tint applied to the highlights in the image.

Shadow Color: The Shadow Color wheel allows you to select the color that will tint the Shadows in your image.

Tint Shadows: Controls the strength of the tint applied to the Shadows in the image.

Balance: Adjusts what DuoTone considers a Shadow vs a Highlight.